In 2013, a study out of Johns Hopkins
led by Frank Lin, M.D., Ph.D., found that older adults with hearing loss are more likely to develop problems thinking and remembering than similarly aged adults with normal hearing. Doctor Lin listed a number of possibilities for the correlation between hearing loss and faster cognitive decline, including ties between hearing loss and social isolation; the brain being forced to devote too much energy to processing sound, thus not expending as much energy on memory and thought processing; and underlying damage that leads to both hearing and cognitive decline.
While all of those possibilities could be reasons for cognitive decline in adults with hearing loss, there is a new study out that points to the third possibility – underlying damage that can cause both hearing loss and cognitive decline.
A new study out of Baycrest Center for Geriatric Care and the University of Memphis in Tennessee
suggests that abnormal function in the brainstem and auditory cortex (the regions that process speech) could be a predictor for dementia.
The study’s senior author, Dr. Claude Alain, professor in the psychology department at the University of Toronto and senior scientist at Baycrest's Rotman Research Institute (RRI), says his team’s research findings open the door to identifying biological markers for dementia because scientists could use the brain’s ability to process speech sounds as a new way to detect mild cognitive impairment (MCI) earlier.
The team, led by Dr. Alain, examined 23 adults between 52 and 86 years of age. None of them had a history of neurologic or psychiatric problems, and all of them had similar hearing acuity. Participants took a dementia screening test and were then separated into two groups. Each participant watched a video while researchers measured the activity in the participants’ brainstems, and they measured brain activity in the auditory cortex while participants identified vowel sounds.
The researchers then analyzed the two sets of data from the measured brain activity and used statistical methods to predict MCI.
Dr. Gavin Bidelman, assistant professor at the University of Memphis and another of the study’s authors, explained that, "When we hear a sound, the normal aging brain keeps the sound in check during processing, but those with MCI seem to have lost this inhibition…since their neural response to the same sounds were over-exaggerated."
The over-exaggerated response to the sounds is considered a functional biomarker, and according to Dr. Bidelman, it could help identify people who should be monitored more closely for cognitive impairment as their risk of developing Alzheimer’s disease and other forms of dementia may be greater than normal.
According to the study results, the results of the electroencephalogram (EEG) the researchers used to measure brain activity during the study along with their statistical analysis helped predict MCI with 80% accuracy – even before adults had been otherwise diagnosed
The study results suggest that there may physical signs of dementia before any cognitive impairment has become apparent. And as we’ve discussed before, getting an early diagnosis – or even just verification that we’re at risk for developing Alzheimer’s – can be helpful. While an earlier diagnosis isn’t a cure, there are treatments and lifestyle changes that may help delay the onset of dementia or slow cognitive decline. Learn the early signs of dementia
, and find out more about what our proprietary Cognitive Therapeutics Method
can do for you or a loved one.